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mLine 29:
Line 29:
→Spacing drainage pipes to reduce groundwater mounding
may be simplified to:
may be simplified to:
<math>Drain\ spacing=\sqrt{\frac{4K_{media}\left(D_{d}-D_{w}\right)^{2}}{q}}</math>
<math>Drain\ spacing=\sqrt{\frac{4K_{media}\left(D_{d}-D_{w}\right)^{2}}{q}}</math>
Where:
{{Plainlist|1=Where:
''K<sub>media</sub> is expressed in m/day
*''K<sub>media</sub> is expressed in m/day
''D<sub>d</sub>'' is the depth to the drain pipe (m)
*''D<sub>d</sub>'' is the depth to the drain pipe (m)
''D<sub>w</sub>'' is the minimum acceptable depth to the water table during infiltration event
*''D<sub>w</sub>'' is the minimum acceptable depth to the water table during infiltration event
''q'' is the inflow volume expressed as a depth over the entire surface (m)
*''q'' is the inflow volume expressed as a depth over the entire surface (m)}}
===Example===
===Example===
During a 25 mm storm event, a bioretention cell receives concentrated flow from a catchment 20 times larger than its own footprint (25 x 20 = 500 mm = 0.5 m).
During a 25 mm storm event, a bioretention cell receives concentrated flow from a catchment 20 times larger than its own footprint (25 x 20 = 500 mm = 0.5 m).